Yet, he is under guardianship by Kim Jung Il's sister - plus, he is always flanked by his father's generals.

Pictures of him do not show a confident or arrogant leader, but rather a rather shellshocked fat boy waiting for someone to kick him in the @ss.

Will N. Korea continue to be the closed off dictatorship with Kim Jong Un as a figurehead - or will he have an active part in the Government?

Depends; if he grows a pair, decides to buck his keepers and goes to his countrymen for support against the military et al, they who revere him will do what he says, like good little brainwashed sheeple do.

i strongly suspect, however, that he'll remain the scared little boy he is, fearful that he, too, will have a "heart attack" and also be replaced.

The NK's seem to have been well-trained to switch their loyalty and obedience---and reverence---just as soon as they're told to. Whaddaya wanna bet that no prisoner will be released? Do you think they, too, cried and wailed when Jong Il died? i'd wager that they did, for they had no doubt what would happen to them if they failed to show "proper respect." i think it more likely than not that all who would defy the "Supreme Leader"(whomever he may be today) have already been killed, and defiance more-or-less bred/trained out of the genetic material.

With goodwill to all the People-

Hatman

"History records that the moneychangers have used every form of abuse, deceit, intrigue, and violent means possible to maintain their control over governments by controlling money and it's issuance."-- James Madison(1751-1836), Father of the Constitution for the USA, 4th US President